Ir's been quite foggy here for the last few days. The quality of light is different. Colour saturation is fairly low. Near the edge of the fog bank the sun looks great, as if there is a huge ND filter in front of it. Anyway, this weekend promises more fog. Are ther any particular tips to get great shots taking advantage of fog?
There are MANY links below...hover over each one to identify where they start and end, and view each example. ;)
Position your camera behind a lone tree or under a forest canopy, and let the filtered sunlight (or moonlight) create rays of light in the fog. Capture trees fading into the fog. Find a lake shore or some islands out on the water, and capture the islands or far shore appearing out of the mist. Elevate yourself above the fog, and shoot down into it.
Use ETTR (see also, What is ETTR (Expose To The Right)?), but moderately, and don't worry about the low contrast (your histogram should have a peak near the right end, but not entirely there, and cover only a portion of your total dynamic range.) Fog will certainly reduce the dynamic range of most scenes, and can create very moody photos. Fog is a GREAT tool for night photography, as it enhances the illumination provided by street lamps, buildings, etc. Fog is also an excellent way to frame silhouettes of pretty much anything, especially if you put the light source directly behind the silhouetted subject...then you also get kind of a halo of light shafts.
I shot a (relatively popular) series of photos in the fog last year at night, feel free to check the EXIF info or the pics for inspiration. Essentially I was using my fastest lens, a 50mm f/1.4, hand held (this flash fog didn't last long, no time for a tripod). I relied on a lot of silhouetting, and city lights (naturally diffused by the fog). The light really had that color, this is not a white-balance mistake.
You can wait till it gets dark, and street lamp create shafts of light, and use those to your advantage. You can also backlight someone (for example with car headlamps) and him look like he's stepping out of a flying saucer.
There will be no or almost no shadows, so textures will mostly disappear, you will have to work exclusively with colors and/or shades of gray. You can use the fog to your advantage since it will very strongly separate objects that are close to the camera from the background.
As other have suggested, if you can get some light source, there is a lot you can do with light in a fog. Shafts of light from street lights or sun beams in a forest, or, with a good lighting, you can make the whole scene look like it's softly glowing.